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22 pages, 2520 KiB

Open AccessArticle

Thermoelectric Properties of Pnma and Rocksalt SnS and SnSe

by Joseph M. Flitcroft, Ioanna Pallikara and Jonathan M. Skelton

Solids 2022, 3(1), 155-176; https://doi.org/10.3390/solids3010011 - 17 Mar 2022

Cited by 11 | Viewed by 4295

Abstract

Thermoelectric materials convert waste heat to electricity and are part of the package of technologies needed to limit global warming. The tin chalcogenides SnS and SnSe are promising candidate thermoelectrics, with orthorhombic SnSe showing some of the highest figures of merit

Z T

[...] Read more.

Thermoelectric materials convert waste heat to electricity and are part of the package of technologies needed to limit global warming. The tin chalcogenides SnS and SnSe are promising candidate thermoelectrics, with orthorhombic SnSe showing some of the highest figures of merit

Z T

reported to date. As for other Group IV chalcogenides, SnS and SnSe can form rocksalt phases under certain conditions, but the thermoelectric properties of these phases are largely unexplored. We have applied a fully ab initio modelling protocol to compare the

Z T

of the orthorhombic and rocksalt phases of SnS and SnSe. Electronic structures from hybrid density-functional theory were used to calculate the three electrical transport properties, including approximate models for the electron relaxation times, and lattice dynamics calculations were performed to model the phonon spectra and lattice thermal conductivities. We obtained good estimates of the

Z T

of the well-studied orthorhombic phases. The rocksalt phases were predicted to show larger electrical conductivities and similar Seebeck coefficients to the orthorhombic phases, resulting in higher thermoelectric power factors, but these were offset by larger thermal conductivities. These results therefore motivate further investigation of the recently discovered “

π

-cubic” phases of SnS and SnSe, which are based on distorted rocksalt supercells, to establish their thermoelectric performance. Full article

(This article belongs to the Special Issue Feature Papers of Solids 2021)

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11 pages, 34547 KiB

Open AccessArticle

Calculation of the Localized Surface Plasmon Resonances of Au Nanoparticles Embedded in NiO

by Maria Tsarmpopoulou, Alexandros G. Chronis, Mihail Sigalas, Alkeos Stamatelatos, Panagiotis Poulopoulos and Spyridon Grammatikopoulos

Solids 2022, 3(1), 55-65; https://doi.org/10.3390/solids3010005 - 28 Jan 2022

Cited by 5 | Viewed by 2955

Abstract

The present article examined the influence of size and periodicity of simulated gold (Au) nanoparticles (NPs) embedded in Nickel Oxide (NiO) matrix on localized plasmonic resonances (LSPRs). The scope of this work is to comparatively study the theoretical outcomes exhibited against the experimental [...] Read more.

The present article examined the influence of size and periodicity of simulated gold (Au) nanoparticles (NPs) embedded in Nickel Oxide (NiO) matrix on localized plasmonic resonances (LSPRs). The scope of this work is to comparatively study the theoretical outcomes exhibited against the experimental results delivered from previous works, including a significant number of simulations and testing of numerous NPs diameter values. A comparison between Au and NiO NPs over silver (Ag) and NiO NPs is also reported to investigate whether the nature of noble metal affects its behavior in terms of LSPRs. The computational results strongly support that the appearance and intensity of LSPRs is straightforward to the increase in the diameter of NPs. The simulation results are in a good agreement with the literature of small NPs, offering the opportunity to further understand the LSPR phenomenon and its more effective implementation to opto-electronic applications. Rigorous Coupled Wave Analysis (RCWA) is performed to stimulate the justification and knowledge of the theoretical conclusions. Full article

(This article belongs to the Special Issue Feature Papers of Solids 2021)

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10 pages, 1200 KiB

Open AccessFeature PaperArticle

Anharmonic Effects in Ordered Kesterite-Type Cu₂ZnSnS₄

by Nicole Suss, Anna Ritscher, Martin Lerch and Ilias Efthimiopoulos

Solids 2021, 2(4), 385-394; https://doi.org/10.3390/solids2040024 - 24 Nov 2021

Cited by 2 | Viewed by 2556

Abstract

We performed an in-depth investigation and analysis of the effect of temperature on the Raman-active A-modes of bulk kesterite-type Cu₂ZnSnS₄ within the 300–460 K temperature range. We acquired the individual contributions to each Raman mode, namely, the thermal expansion and [...] Read more.

We performed an in-depth investigation and analysis of the effect of temperature on the Raman-active A-modes of bulk kesterite-type Cu₂ZnSnS₄ within the 300–460 K temperature range. We acquired the individual contributions to each Raman mode, namely, the thermal expansion and anharmonic interactions terms responsible for the Raman shift and broadening with temperature. Our results indicate that the Raman shift with temperature is dominated by the thermal expansion term, whereas the broadening is mainly governed by three-phonon damping processes in this material. Considering relevant results from the literature, it appears that dimensionality is a key factor in regulating the dominant phonon decay mechanism. Full article

(This article belongs to the Special Issue Feature Papers of Solids 2021)

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14 pages, 3933 KiB

Open AccessArticle

A Scintillating One-Dimensional Coordination Polymer Based on Cadmium(II), N,N′-(1,4-Phenylenedicarbonyl)diglycinate, and 2,2′-Bipyridine: Crystal Structure, Hirshfeld Surface Analysis, and Luminescence Lifetime Properties ^†

by Niels-Patrick Pook

Solids 2021, 2(4), 371-384; https://doi.org/10.3390/solids2040023 - 13 Nov 2021

Cited by 1 | Viewed by 3174

Abstract

In recent years, several coordination polymers of different dimensions and metal–organic frameworks were tested and expected to be good candidates for closing the gap between organic and plastic scintillators on the one hand side and inorganic scintillators on the other hand side. In [...] Read more.

In recent years, several coordination polymers of different dimensions and metal–organic frameworks were tested and expected to be good candidates for closing the gap between organic and plastic scintillators on the one hand side and inorganic scintillators on the other hand side. In the present work, we report the synthesis and characterization of a novel one-dimensional scintillating coordination polymer based on cadmium(II), N,N′-(1,4-phenylenedicarbonyl)di-glycinate, and 2,2′-bipyridine. Crystals could be obtained from water–methanol solutions and the structure was determined by single-crystal diffraction. The coordination polymer exhibits scintillation under X-ray excitation and laser as well as UV-light induced photoluminescence with fast decay times. Photoluminescence and X-ray excited optical luminescence (XEOL) properties and decay times were performed using a two-dimensional photon counting streak camera system with a time resolution up to 20 ps. The non-covalent interactions and supramolecular assemblies as a potential multiplier of the scintillating effect were investigated with the aid of a Hirshfeld surface analysis. The quality and phase purity of the used crystals and pellets was clarified by powder diffraction and Rietveld refinement. Full article

(This article belongs to the Special Issue Feature Papers of Solids 2021)

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17 pages, 16884 KiB

Open AccessArticle

Embedded Resistance Wire Technique for Epoxy Curing and Self-Healing of PET Thermoplastics

by Lykourgos C. Kontaxis, Athanasios Kotrotsos, Spyros Verbis and George C. Papanicolaou

Solids 2021, 2(3), 314-330; https://doi.org/10.3390/solids2030020 - 3 Sep 2021

Viewed by 3225

Abstract

The aim of the present study is to apply an embedded resistance wire technique for curing of thermosetting resins as well as for the self-healing of thermoplastic polymers. The work consists of two parts. In the first part, Kanthal resistance wires embedded in [...] Read more.

The aim of the present study is to apply an embedded resistance wire technique for curing of thermosetting resins as well as for the self-healing of thermoplastic polymers. The work consists of two parts. In the first part, Kanthal resistance wires embedded in a resin plate acted as heating elements when direct electrical current was flowing through them (Joule heating). During heating, the temperature was continuously monitored using a thermal camera, and accurate temperature times for fixed position diagrams as well as temperature positions for fixed time diagrams were calculated. The effects of curing with this method were evaluated by studying the three-point bending mechanical behavior of the cured resin, comparing it with the corresponding behavior of the same resin when cured using a conventional oven curing method at the same temperature. In the second part of the present work, the possibility of using the same technique for healing existing notches and flaws in a PET thermoplastic is explored. We examined whether providing energy through the resistance wires created the right amount of heat to heal the thermoplastic, or, more specifically, whether it closed the notches and eliminated the abrasions that were artificially created on the specimens. The technique using embedded resistance wires worked equally well, with interesting and promising preliminary results regarding the curing of thermoset resins and the healing of thermoplastics. Full article

(This article belongs to the Special Issue Feature Papers of Solids 2021)

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15 pages, 3091 KiB

Open AccessArticle

The Effect of the Formation of Superelastic NiTi Phase on Static and Dynamic Corrosion Performance of Ni-P Coating

by Zhi Li and Zoheir Farhat

Solids 2021, 2(3), 278-292; https://doi.org/10.3390/solids2030018 - 2 Aug 2021

Cited by 2 | Viewed by 2695

Abstract

The addition of superelastic NiTi particles is a great benefit to the toughness of the Ni-P coating. Nonetheless, NiTi nanopowder costs 10 times more than Ti nanopowder. Therefore, in the present study, to reduce the cost, Ni-P-NiTi composite coatings were prepared on AISI [...] Read more.

The addition of superelastic NiTi particles is a great benefit to the toughness of the Ni-P coating. Nonetheless, NiTi nanopowder costs 10 times more than Ti nanopowder. Therefore, in the present study, to reduce the cost, Ni-P-NiTi composite coatings were prepared on AISI 1018 steel substrates by the electroless incorporation of Ti nanoparticles into Ni-P followed by the annealing of Ni-P-Ti coatings. The effect of the formation of a superelastic NiTi phase on static and dynamic corrosion performance was investigated. It was found that the annealed Ni-P-Ti coating (i.e., Ni-P-NiTi coating) has much higher static corrosion resistance than the as-deposited Ni-P coating. The dynamic corrosion rates in the absence of abrasive particles are 10 times higher than the static corrosion rates of the coatings. The dynamic corrosion rates in the presence of abrasive particles are one order of magnitude higher than the dynamic corrosion rates in the absence of abrasive particles. The formation of a superelastic NiTi phase considerably improved the static and dynamic corrosion performance of the Ni-P coating. In the absence of abrasive particles under flowing condition, the dynamic corrosion resistance of the annealed Ni-P-Ti coating (i.e., Ni-P-NiTi coating) is 19 times higher than that of the as-deposited Ni-P coating. In the most aggressive environment (in the presence of abrasive particles), the dynamic corrosion resistance of the annealed Ni-P-Ti coating (i.e., Ni-P-NiTi coating) is four times higher than that of the as-deposited Ni-P coating. The annealed Ni-P-Ti coating (i.e., Ni-P-NiTi coating) can be used in applications where high corrosion resistance is required, especially in an extremely aggressive environment. Full article

(This article belongs to the Special Issue Feature Papers of Solids 2021)

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13 pages, 3782 KiB

Open AccessArticle

Protonated Forms of Layered Perovskite-Like Titanate NaNdTiO₄: Neutron and X-ray Diffraction Structural Analysis

by Oleg I. Silyukov, Sergey A. Kurnosenko, Iana A. Minich, Ivan A. Rodionov and Irina A. Zvereva

Solids 2021, 2(3), 265-277; https://doi.org/10.3390/solids2030017 - 1 Jul 2021

Cited by 5 | Viewed by 3677

Abstract

Structures of partially and completely protonated Ruddlesden–Popper phases, H_0.7Na_0.3NdTiO₄·0.3H₂O and HNdTiO₄, have been established by means of neutron and X-ray diffraction analysis and compared among themselves as well as with that of the [...] Read more.

Structures of partially and completely protonated Ruddlesden–Popper phases, H_0.7Na_0.3NdTiO₄·0.3H₂O and HNdTiO₄, have been established by means of neutron and X-ray diffraction analysis and compared among themselves as well as with that of the initial titanate NaNdTiO₄. It was shown that while interlayer sodium cations in the partially protonated form are coordinated by nine oxygen atoms, including one related to intercalated water, in the fully protonated compound the ninth oxygen proves to be an axial anion belonging to the opposite slab of titanium-oxygen octahedra. Moreover, the partially protonated titanate was found to significantly differ from the other two in the octahedron distortion pattern. It is characterized by a weakly pronounced elongation of the octahedra towards the Nd-containing interlayer space making Ti⁴⁺ cations practically equidistant from both axial oxygen atoms, which is accompanied by a low-frequency shift of the bands relating to the asymmetric stretching mode of axial Ti–O bonds observed in the Raman spectra. Full article

(This article belongs to the Special Issue Feature Papers of Solids 2021)

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16 pages, 1495 KiB

Open AccessFeature PaperArticle

Dynamics and Elastic Properties of Glassy Metastable States

by Keiko M. Aoki

Solids 2021, 2(2), 249-264; https://doi.org/10.3390/solids2020016 - 4 Jun 2021

Cited by 3 | Viewed by 3625

Abstract

By a molecular dynamics (MD) simulation method which ensures the system will be under hydrostatic pressure, dynamic and elastic properties of glassy metatstable states are investigated. In the MD method, the simulation cell fluctuates not only in volume but also in shape under [...] Read more.

By a molecular dynamics (MD) simulation method which ensures the system will be under hydrostatic pressure, dynamic and elastic properties of glassy metatstable states are investigated. In the MD method, the simulation cell fluctuates not only in volume but also in shape under constant hydrostatic pressure and temperature. As observed in experiments for many glass forming materials, metastable states in our simulation show a sharp increase in mean-square-displacement at certain temperatures

T_{D}

. Dynamic heterogeneity is also observed at

T_{D}

. Elastic properties are calculated from stress and strain relations obtained from the spontaneous fluctuation of internal stress tensor and simulation cell parameters. Each investigated state shows distinctive dynamics while maintaining solid-like elastic properties. The elastic properties stay intact even above

T_{D}

. It has been shown that the rigidity and mobility of glassy metastable states are compatible under dynamic heterogeneity. Full article

(This article belongs to the Special Issue Feature Papers of Solids 2021)

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20 pages, 3988 KiB

Open AccessArticle

Characterisation and Traceability of Calcium Carbonate from the Seaweed Lithothamnium calcareum

by Rosana Pereira da Silva, Giovanna Sayuri Domingues Kawai, Fabio Ramos Dias de Andrade, Vinicius Danilo Nonato Bezzon and Humberto Gomes Ferraz

Solids 2021, 2(2), 192-211; https://doi.org/10.3390/solids2020013 - 6 May 2021

Cited by 9 | Viewed by 8707

Abstract

Calcium carbonate (CaCO₃) from the seaweed Lithothamnium calcareum is a suitable dietary supplement for the prevention of osteoporosis, due to its chemical composition. This study compared CaCO₃ from L. calcareum to CaCO₃ from oyster shell and inorganic minerals that [...] Read more.

Calcium carbonate (CaCO₃) from the seaweed Lithothamnium calcareum is a suitable dietary supplement for the prevention of osteoporosis, due to its chemical composition. This study compared CaCO₃ from L. calcareum to CaCO₃ from oyster shell and inorganic minerals that are already used in the pharmaceutical industry. The Rietveld refinement of the XRD showed that the mineral fraction of L. calcareum is composed of aragonite (50.3 wt%), magnesian calcite (45.3 wt%), calcite (4.4 wt%), comin contrast to oyster shell and inorganic minerals, which contain only calcite. The morphology of L. calcareum carbonate particles is granular xenomorphic, which is distinct from the scalenohedral form of inorganic calcite and the fibrous and scale-like fragments of oyster shell. The crystal structures of aragonite and magnesian calcite, present in L. calcareum, have higher contents of oligoelements than the pure calcite in other materials. The isotopic composition (stable isotopes of carbon and oxygen) is heavy in the CaCO₃ from L. calcareum (δ¹³C = 1.1‰; δ¹⁸O = −0.1‰) and oyster shell (δ¹³C = −4‰; δ¹⁸O = −2.8‰) in marked contrast to the much lighter isotopic composition of inorganic mineral CaCO₃ (δ¹³C = −19.2‰; δ¹⁸O = −26.3‰). The differences indicated above were determined through principal component analysis, where the first and second principal components are sufficient for the clear distinction and traceability of CaCO₃ sources. Full article

(This article belongs to the Special Issue Feature Papers of Solids 2021)

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15 pages, 10509 KiB

Open AccessArticle

Evaluation of ((La_0.60Sr_0.40)_0.95Co_0.20Fe_0.80O_3-x)-Ag Composite Anode for Direct Ammonia Solid Oxide Fuel Cells and Effect of Pd Impregnation on the Electrochemical Performance

by Shambhu Singh Rathore, Aniruddha P. Kulkarni, Daniel Fini, Sarbjit Giddey and Aaron Seeber

Solids 2021, 2(2), 177-191; https://doi.org/10.3390/solids2020012 - 3 May 2021

Cited by 9 | Viewed by 4846

Abstract

Ammonia produced using renewable hydrogen is being viewed as a promising media for the export of energy from locations rich in renewable energy sources. Solid oxide fuel cells (SOFCs) are efficient devices for converting such exported ammonia back into electricity at the point [...] Read more.

Ammonia produced using renewable hydrogen is being viewed as a promising media for the export of energy from locations rich in renewable energy sources. Solid oxide fuel cells (SOFCs) are efficient devices for converting such exported ammonia back into electricity at the point of use; however, investigations on materials and operating regimes for direct ammonia fuelled SOFCs are limited. In this work, we evaluated the direct ammonia SOFC performance with a Silver-Lanthanum Strontium Cobalt Ferrite (Ag-LSCF) composite anode and a novel Palladium (Pd) nanoparticle decorated Silver-Lanthanum Strontium Cobalt Ferrite (Pd-Ag-LSCF) composite anode in the temperature range of 500 °C to 800 °C. It is hypothesised that palladium nanoparticles in the anode provide hydrogen dissolution and shift the ammonia decomposition reaction towards the right. The cell performance was evaluated with both hydrogen and ammonia as fuels and a clear-cut improvement in the performance was observed with the addition of Pd for both the fuels. The results showed performance enhancements of 20% and 43% with hydrogen and ammonia fuels, respectively, from the addition of Pd to the Ag-LSCF anode. Open-circuit voltage (OCV) values of the cells with hydrogen and ammonia fuels recorded over the temperature range of 500 °C to 800 °C indicated the possibility of direct electro-oxidation of ammonia in SOFCs. Full article

(This article belongs to the Special Issue Feature Papers of Solids 2021)

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12 pages, 2367 KiB

Open AccessArticle

Thermal Decomposition of [AH][M(HCOO)₃] Perovskite-Like Formates

by Lilián Claudia Gómez-Aguirre, Jorge Otero-Canabal, Manuel Sánchez-Andújar, María Antonia Señarís-Rodríguez, Socorro Castro-García and Breogán Pato-Doldán

Solids 2021, 2(2), 165-176; https://doi.org/10.3390/solids2020011 - 2 May 2021

Cited by 3 | Viewed by 4133

Abstract

A systematic study of the thermal decomposition of hybrid perovskites of formula [AH][M(HCOO)₃] under inert atmosphere was performed by means of thermogravimetry and simultaneous infrared spectroscopy of the evolved gases. The influence of: (i) the metal ion of the [M(HCOO)₃ [...] Read more.

A systematic study of the thermal decomposition of hybrid perovskites of formula [AH][M(HCOO)₃] under inert atmosphere was performed by means of thermogravimetry and simultaneous infrared spectroscopy of the evolved gases. The influence of: (i) the metal ion of the [M(HCOO)₃]^- framework and (ii) the guest [AH]⁺ cation, in the composition of the final residue was evaluated. In this work, it has been demonstrated that these materials can be used as precursors of metal or metal-oxide compounds—obtained free of carbon—, and that the composition of the final residue is determined by the standard reduction potential of the metal cation of the framework. Full article

(This article belongs to the Special Issue Feature Papers of Solids 2021)

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10 pages, 1621 KiB

Open AccessFeature PaperArticle

An Evaluation of Optical Absorbance Kinetics for the Detection of Micro-Porosity in Molecularly Doped Polymer Thin-Films

by David Mitchell Goldie, Orlaith Skelton and Thomas James Bailey

Solids 2021, 2(2), 155-164; https://doi.org/10.3390/solids2020010 - 1 Apr 2021

Viewed by 2994

Abstract

The use of optical absorbance kinetics to identify micro-porous regions in doped polymer films is evaluated. Data are presented for a series of hydrazone doped polymer films which are found to optically bleach upon exposure to an ultra violet (UV) radiation source. The [...] Read more.

The use of optical absorbance kinetics to identify micro-porous regions in doped polymer films is evaluated. Data are presented for a series of hydrazone doped polymer films which are found to optically bleach upon exposure to an ultra violet (UV) radiation source. The UV absorbance kinetics are found to exhibit distinctive characteristics for the various polymers studied, with changes in film absorbance occurring either in a fast (<10³ s) or slow (>10⁴ s) timescale. An interpretation of these distinctive timescales based upon a cellular-automata model of the absorbance kinetics suggests that the underlying photo-oxidation of the hydrazone is highly sensitive to underlying micro-porosity in the films which controls the necessary supply of absorbed oxygen for photo-cyclic reaction. Full article

(This article belongs to the Special Issue Feature Papers of Solids 2021)

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10 pages, 3244 KiB

Open AccessArticle

Contactless Determination of Electric Field in Metal–Insulator–Semiconductor Interfaces by Using Constant DC-Reflectivity Photoreflectance

by Eiichi Kobayashi, Koya Satta, Ryoga Inoue, Ken Suzuki and Takayuki Makino

Solids 2021, 2(2), 129-138; https://doi.org/10.3390/solids2020008 - 29 Mar 2021

Viewed by 3568

Abstract

We applied photoreflectance (PR) spectroscopy for contactless determination of the electric field strength at buried interfaces in metal–insulator–semiconductor (MIS) structures. The PR is an all-optical version of an electromodulated reflectance spectroscopy. The tradeoff of this adoption is that this requires an additional feedback [...] Read more.

We applied photoreflectance (PR) spectroscopy for contactless determination of the electric field strength at buried interfaces in metal–insulator–semiconductor (MIS) structures. The PR is an all-optical version of an electromodulated reflectance spectroscopy. The tradeoff of this adoption is that this requires an additional feedback system to eliminate background problems induced by scattered pump light and/or photoluminescence. A microcomputer-based feedback system has been developed for this elimination. Despite the very tiny signal intensity, we successfully attained a sufficiently good signal–noise ratio to determine the electric field strength in oxide-based MIS interfaces that exhibits a large, unwanted photoluminescence signal. The field strength was evaluated to be ca. 0.25 kV/cm. Full article

(This article belongs to the Special Issue Feature Papers of Solids 2021)

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8 pages, 1442 KiB

Open AccessArticle

Heat Capacities of Nanostructured Wurtzite and Rock Salt ZnO: Challenges of ZnO Nano-Phase Diagram

by Konstantin V. Kamenev, Alexandre Courac, Petr S. Sokolov, Andrei N. Baranov, Felix Yu. Sharikov and Vladimir L. Solozhenko

Solids 2021, 2(1), 121-128; https://doi.org/10.3390/solids2010007 - 1 Mar 2021

Cited by 2 | Viewed by 3937

Abstract

Low-temperature heat capacities (C_p) of nanostructured rock salt (rs-ZnO) and wurtzite (w-ZnO) polymorphs of zinc oxide were measured in the 2–315 K temperature range. No significant influence of nanostructuring on C_p of w-ZnO has been observed. The measured C [...] Read more.

Low-temperature heat capacities (C_p) of nanostructured rock salt (rs-ZnO) and wurtzite (w-ZnO) polymorphs of zinc oxide were measured in the 2–315 K temperature range. No significant influence of nanostructuring on C_p of w-ZnO has been observed. The measured C_p of rock salt ZnO is lower than that of wurtzite ZnO below 100 K and is higher above this temperature. Using available thermodynamic data, we established that the equilibrium pressure between nanocrystalline w-ZnO and rs-ZnO is close to 4.6 GPa at 300 K (half as much as the onset pressure of direct phase transformation) and slightly changes with temperature up to 1000 K. Full article

(This article belongs to the Special Issue Feature Papers of Solids 2021)

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11 pages, 5048 KiB

Open AccessFeature PaperArticle

Ce-Doped-MgAl Superhydrophobic Layered Double Hydroxide for Enhanced Corrosion Resistance Properties

by Muhammad Ahsan Iqbal, Humaira Asghar and Michele Fedel

Solids 2021, 2(1), 76-86; https://doi.org/10.3390/solids2010004 - 16 Feb 2021

Cited by 6 | Viewed by 3321

Abstract

Double doped layered double hydroxide thin films were developed directly on the aluminum substrate in two steps: Initially cerium-based MgAl-layered double hydroxide (LDH) were synthesized directly on the anodic aluminum surface via the in situ growth method, and were then modified with the [...] Read more.

Double doped layered double hydroxide thin films were developed directly on the aluminum substrate in two steps: Initially cerium-based MgAl-layered double hydroxide (LDH) were synthesized directly on the anodic aluminum surface via the in situ growth method, and were then modified with the stearate anions through an ion-exchange mechanism to achieve compact multifunctional protective thin films. The structural and morphological characteristics of the developed LDH films were investigated, and the surface contact angle measurements (CA) and self-cleaning properties were analyzed. The obtained double doped LDH film displayed the superhydrophobic characteristic with a water contact angle of ~155°. Furthermore, the superhydrophobic behavior of LDH on exposure to UV radiation (λ = 310 nm) was examined to evaluate outdoor applications. Long-term Electrochemical Impedance Spectroscopy (EIS) analysis was performed to understand the corrosion resistance properties. The introduction of double doped LDHs demonstrates significantly higher corrosion resistance properties than only cerium-modified LDHs and has shown superior stability against 0.1 M NaCl solution. Full article

(This article belongs to the Special Issue Feature Papers of Solids 2021)

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10 pages, 1832 KiB

Open AccessArticle

Towards Recognition of Scale Effects in a Solid Model of Lattices with Tensegrity-Inspired Microstructure

by Wojciech Gilewski and Anna Al Sabouni-Zawadzka

Solids 2021, 2(1), 50-59; https://doi.org/10.3390/solids2010002 - 20 Jan 2021

Cited by 2 | Viewed by 2338

Abstract

This paper is dedicated to the extended solid (continuum) model of tensegrity structures or lattices. Tensegrity is defined as a pin-joined truss structure with an infinitesimal mechanism stabilized by a set of self-equilibrated normal forces. The proposed model is inspired by the continuum [...] Read more.

This paper is dedicated to the extended solid (continuum) model of tensegrity structures or lattices. Tensegrity is defined as a pin-joined truss structure with an infinitesimal mechanism stabilized by a set of self-equilibrated normal forces. The proposed model is inspired by the continuum model that matches the first gradient theory of elasticity. The extension leads to the second- or higher-order gradient formulation. General description is supplemented with examples in 2D and 3D spaces. A detailed form of material coefficients related to the first and second deformation gradients is presented. Substitute mechanical properties of the lattice are dependent on the cable-to-strut stiffness ratio and self-stress. Scale effect as well as coupling of the first and second gradient terms are identified. The extended solid model can be used for the evaluation of unusual mechanical properties of tensegrity lattices. Full article

(This article belongs to the Special Issue Feature Papers of Solids 2021)

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Review

Jump to: Research

20 pages, 40375 KiB

Open AccessFeature PaperReview

Recent Advances in the Use of Transition-Metal Porphyrin and Phthalocyanine Complexes as Electro-Catalyst Materials on Modified Electrodes for Electroanalytical Sensing Applications

by J. Antonio Cruz-Navarro, Fabiola Hernández-García, Luis Humberto Mendoza-Huizar, Verónica Salazar-Pereda, J. Ángel Cobos-Murcia, Raúl Colorado-Peralta and Giaan Arturo Álvarez-Romero

Solids 2021, 2(2), 212-231; https://doi.org/10.3390/solids2020014 - 6 May 2021

Cited by 18 | Viewed by 5499

Abstract

Metalloporphyrins (MP) and metallophtalocyanines (MPc) are innovative materials with catalytic properties that have attracted attention for their application for diverse electrochemical purposes. The presence of metallic centers in their structure offers a redox-active behavior that is being applied in the design of solid [...] Read more.

Metalloporphyrins (MP) and metallophtalocyanines (MPc) are innovative materials with catalytic properties that have attracted attention for their application for diverse electrochemical purposes. The presence of metallic centers in their structure offers a redox-active behavior that is being applied in the design of solid electrodes for the quantification of biomolecules, water contaminants, and pharmaceuticals, among others. Herein, we collect the recent information about porphyrin and phthalocyanine complexes as modifiers of electrodes, and the important aspects of the design, characterization, and application of these electrodes. Full article

(This article belongs to the Special Issue Feature Papers of Solids 2021)

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13 pages, 1748 KiB

Open AccessReview

Use of Dynamic Mechanical Analysis (DMA) for Characterizing Interfacial Interactions in Filled Polymers

by Muhammad Ahsan Bashir

Solids 2021, 2(1), 108-120; https://doi.org/10.3390/solids2010006 - 1 Mar 2021

Cited by 110 | Viewed by 11387

Abstract

Dynamic mechanical analysis (DMA) provides reliable information about the viscoelastic behavior of neat and filled polymers. The properties of filled polymers are relevant to different industries as protective organic coatings, composites etc. Interfacial interactions in filled polymers play an important role in determining [...] Read more.

Dynamic mechanical analysis (DMA) provides reliable information about the viscoelastic behavior of neat and filled polymers. The properties of filled polymers are relevant to different industries as protective organic coatings, composites etc. Interfacial interactions in filled polymers play an important role in determining their bulk properties and performance during service life. In this brief review article, studies that used DMA to characterize the interfacial interactions in filled polymers have been reviewed. The available open literature provides a mixed opinion about the influence of interfacial interactions on the glass transition temperature of filled polymers. Nevertheless, it appears that in the case of strong interfacial interactions between the filler particles and the polymeric matrix, the peak value of tan δ is reduced in comparison to that of a filled polymer where these interactions are weak. Full article

(This article belongs to the Special Issue Feature Papers of Solids 2021)

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21 pages, 2660 KiB

Open AccessFeature PaperReview

Thermal Expansion Behavior in the A₂M₃O₁₂ Family of Materials

by Hongfei Liu, Weikang Sun, Zhiping Zhang, La’Nese Lovings and Cora Lind

Solids 2021, 2(1), 87-107; https://doi.org/10.3390/solids2010005 - 19 Feb 2021

Cited by 41 | Viewed by 5114

Abstract

Over the past several decades, research on anomalous thermal expansion materials has been rapidly growing, and increasing numbers of compounds exhibiting negative thermal expansion (NTE) have been reported. In particular, compounds with formula A₂M₃O₁₂ have attracted considerable attention. [...] Read more.

Over the past several decades, research on anomalous thermal expansion materials has been rapidly growing, and increasing numbers of compounds exhibiting negative thermal expansion (NTE) have been reported. In particular, compounds with formula A₂M₃O₁₂ have attracted considerable attention. A₂M₃O₁₂ family materials offer a wide range of possible compositions due to the chemical flexibility of the A and M sites. According to published research, more than half of them possess NTE properties. This paper reviews the range of physical properties displayed by materials in the A₂M₃O₁₂ family. Research on improving material imperfections and controlling the coefficient of thermal expansion in the A₂M₃O₁₂ family are systematically summarized. Finally, challenges and questions about the developments of these A₂M₃O₁₂ NTE compounds in future studies are also discussed. Full article

(This article belongs to the Special Issue Feature Papers of Solids 2021)

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16 pages, 392 KiB

Open AccessReview

Solid Dispersions of Anthelmintics and Plant Protection Preparations

by Salavat S. Khalikov

Solids 2021, 2(1), 60-75; https://doi.org/10.3390/solids2010003 - 6 Feb 2021

Cited by 6 | Viewed by 2956

Abstract

Because of the rapid development of nanotechnologies, materials, in particular, solid dispersions (SDs), which are actively introduced into the life of modern man, have been obtained. Special progress in this area is observed in industry and medicine. The use of SDs in agriculture [...] Read more.

Because of the rapid development of nanotechnologies, materials, in particular, solid dispersions (SDs), which are actively introduced into the life of modern man, have been obtained. Special progress in this area is observed in industry and medicine. The use of SDs in agriculture is lagging far behind, despite the growing number of scientific papers on this topic. At the same time, the prospects for the introduction of SDs in the agro-industrial complex are obvious. The review presents the results of research on the development of innovative preparations based on SD to protect plants from diseases and pests of cultivated plants, as well as parasiticides to protect animal health based on modern achievements of nanotechnology. One of these technologies is the methods of mechanochemistry, which improve the properties of poorly soluble biologically active substances by their joint mechanical treatment with water-soluble polymers and auxiliary substances. Full article

(This article belongs to the Special Issue Feature Papers of Solids 2021)

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49 pages, 6363 KiB

Open AccessFeature PaperReview

Composition, Thermal Expansion and Phase Transitions in Framework Silicates: Revisitation and Review of Natural and Synthetic Analogues of Nepheline-, Feldspar- and Leucite-Mineral Groups

by C. Michael B. Henderson

Solids 2021, 2(1), 1-49; https://doi.org/10.3390/solids2010001 - 5 Jan 2021

Cited by 12 | Viewed by 4925

Abstract

Framework silicates form about 70% of the Earth’s crust, mainly feldspars ~50–60% and quartz ~10–15%. Less-abundant feldspathoids include nepheline-, leucite-, and sodalite-group minerals, rich in structurally challenging properties. This review paper deals with anhydrous feldspar-, nepheline-, and leucite/pollucite groups, emphasising the importance of [...] Read more.

Framework silicates form about 70% of the Earth’s crust, mainly feldspars ~50–60% and quartz ~10–15%. Less-abundant feldspathoids include nepheline-, leucite-, and sodalite-group minerals, rich in structurally challenging properties. This review paper deals with anhydrous feldspar-, nepheline-, and leucite/pollucite groups, emphasising the importance of parallel studies on natural and synthetic samples. Four topics are covered. For decades, petrologists have analysed nephelines and recalculated their compositions as endmember molecules but, by not following rules of stuffed-tridymite crystal chemistry, have not estimated reliably the excess SiO₂ present in solid solution. Some materials scientists make similar mistakes, and a new approach is described here. Synthesis studies of analogue feldspars, nephelines, and leucite/pollucites led to collaborative studies, mainly using laboratory and synchrotron X-ray powder diffraction methods at room and elevated temperatures, to study thermal expansion and displacive phase transitions. Such work was recently expanded to address the spontaneous strain relations. Topics covered here include work on nepheline/kalsilite analogues in the system SrAl₂O₄—BaAl₂O₄; thermal expansion of (K,Na)Al-, RbAl-, RbGa-, and SrAl-feldspars; and thermal expansion and phase transitions in analogue leucites KGaSi₂O₆ (tetragonal to cubic) and K₂MgSi₅O₁₂ (monoclinic to orthorhombic). Results are reviewed in the context of research published in mineralogical and more-widely in physical sciences journals. Full article

(This article belongs to the Special Issue Feature Papers of Solids 2021)

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